SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3404d48f760867658b6a97fffd6c5df41c20f620b888afab61fd59dc1699ebe7' 
  AND token = 'mADVoz4cPfs/XZYiAvOHbeKXfGrN2UgiiboeFrstelc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}